// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* atmel-pcm-dma.c -- ALSA PCM DMA support for the Atmel SoC.
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*
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* Copyright (C) 2012 Atmel
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*
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* Author: Bo Shen <voice.shen@atmel.com>
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*
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* Based on atmel-pcm by:
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* Sedji Gaouaou <sedji.gaouaou@atmel.com>
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* Copyright 2008 Atmel
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#include <linux/dma-mapping.h>
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#include <linux/dmaengine.h>
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#include <linux/atmel-ssc.h>
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#include <sound/core.h>
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#include <sound/pcm.h>
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#include <sound/pcm_params.h>
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#include <sound/soc.h>
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#include <sound/dmaengine_pcm.h>
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#include "atmel-pcm.h"
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/*--------------------------------------------------------------------------*\
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* Hardware definition
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\*--------------------------------------------------------------------------*/
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static const struct snd_pcm_hardware atmel_pcm_dma_hardware = {
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.info = SNDRV_PCM_INFO_MMAP |
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SNDRV_PCM_INFO_MMAP_VALID |
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SNDRV_PCM_INFO_INTERLEAVED |
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SNDRV_PCM_INFO_RESUME |
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SNDRV_PCM_INFO_PAUSE,
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.period_bytes_min = 256, /* lighting DMA overhead */
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.period_bytes_max = 2 * 0xffff, /* if 2 bytes format */
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.periods_min = 8,
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.periods_max = 1024, /* no limit */
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.buffer_bytes_max = 512 * 1024,
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};
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/*
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* atmel_pcm_dma_irq: SSC interrupt handler for DMAENGINE enabled SSC
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*
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* We use DMAENGINE to send/receive data to/from SSC so this ISR is only to
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* check if any overrun occured.
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*/
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static void atmel_pcm_dma_irq(u32 ssc_sr,
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struct snd_pcm_substream *substream)
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{
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struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
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struct atmel_pcm_dma_params *prtd;
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prtd = snd_soc_dai_get_dma_data(asoc_rtd_to_cpu(rtd, 0), substream);
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if (ssc_sr & prtd->mask->ssc_error) {
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if (snd_pcm_running(substream))
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pr_warn("atmel-pcm: buffer %s on %s (SSC_SR=%#x)\n",
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substream->stream == SNDRV_PCM_STREAM_PLAYBACK
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? "underrun" : "overrun", prtd->name,
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ssc_sr);
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/* stop RX and capture: will be enabled again at restart */
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ssc_writex(prtd->ssc->regs, SSC_CR, prtd->mask->ssc_disable);
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snd_pcm_stop_xrun(substream);
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/* now drain RHR and read status to remove xrun condition */
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ssc_readx(prtd->ssc->regs, SSC_RHR);
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ssc_readx(prtd->ssc->regs, SSC_SR);
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}
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}
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static int atmel_pcm_configure_dma(struct snd_pcm_substream *substream,
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struct snd_pcm_hw_params *params, struct dma_slave_config *slave_config)
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{
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struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
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struct atmel_pcm_dma_params *prtd;
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struct ssc_device *ssc;
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int ret;
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prtd = snd_soc_dai_get_dma_data(asoc_rtd_to_cpu(rtd, 0), substream);
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ssc = prtd->ssc;
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ret = snd_hwparams_to_dma_slave_config(substream, params, slave_config);
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if (ret) {
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pr_err("atmel-pcm: hwparams to dma slave configure failed\n");
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return ret;
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}
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slave_config->dst_addr = ssc->phybase + SSC_THR;
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slave_config->dst_maxburst = 1;
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slave_config->src_addr = ssc->phybase + SSC_RHR;
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slave_config->src_maxburst = 1;
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prtd->dma_intr_handler = atmel_pcm_dma_irq;
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return 0;
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}
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static const struct snd_dmaengine_pcm_config atmel_dmaengine_pcm_config = {
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.prepare_slave_config = atmel_pcm_configure_dma,
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.pcm_hardware = &atmel_pcm_dma_hardware,
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.prealloc_buffer_size = 64 * 1024,
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};
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int atmel_pcm_dma_platform_register(struct device *dev)
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{
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return devm_snd_dmaengine_pcm_register(dev,
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&atmel_dmaengine_pcm_config, 0);
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}
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EXPORT_SYMBOL(atmel_pcm_dma_platform_register);
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MODULE_AUTHOR("Bo Shen <voice.shen@atmel.com>");
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MODULE_DESCRIPTION("Atmel DMA based PCM module");
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MODULE_LICENSE("GPL");
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